About API 16A Segmented Dual Completion Flanges

Segmented Dual Completion Flanges

They have one flat side with either 5 or 6 bolt holes.

These flanges, designed for use as integral flanges in/on well head christmas trees that complete two producing zones from a single cased well bore, appear in API Spec 6A, 19th Ed. Earlier editions of API Spec 6A once included designs that allowed triple and quadruple completions, but these Segmented Flanges last appeared in API Spec 6A, 14th Ed. and do not interchange with dual completion flanges.

Manufacturers have introduced “Block Valves” for multiple completion well heads and no longer offer Segmented Flanges for triple and quadruple completions. Segmented Flanges seal with ring gaskets and have a recessed face that may (should) allow face to face make-up. This feature adds stability to the otherwise awkward design of the flange type.

API Spec 6A specifies that use of this flange form requires their use in sets (Pairs). The bodies, integral with the flanges, shall have a rigid connection between them to add structural stability to the assembly. Special flange adapter spools with a standard flange on one end and a Segmented Flange on the other may allow attachment of workover BOP’s to dual completion heads.

FLANGE X SEGMENTED ADAPTER SPOOL

(A) NOMINAL CONNECTION

(B) NOMINAL SEGMENTED FLANGE API Spec 6A specifically states that Segmented Flanges shall not have corrosion resistant ring grooves, and Operators shall not use these flanges in Hydrogen Sulfide Service (HSS). Manufacturers shall not mark these flanges DD, EE, FF, and/or HH.